Method and apparatus for taking out piston in trunk piston engine

ABSTRACT

Method of taking the piston from the engine in the internal combustion engine, more particularly in the trunk piston engine, characterized by that the connecting rod is disconnected from the piston and turned to a suitable position in the crankcase, the piston is drawn out of the cylinder to the crankshaft and supported on the crankshaft, and the crankshaft is rotated together with the piston to the position where the piston is taken out of the engine.

atent [191 Okaz aki Jan. 22, 1974 METHOD AND APPARATUS FOR TAKING FOREIGN PATENTS OR APPLICATIONS I R K OUT PISTON N T UN PISTON ENGINE 512,287 10/1930 Germany 123/195 R [75] Inventor: Takeo Olrazaki, Tokyo, Japan 960,578 10/1949 France .1 123/195 R 73] Assignees: Mitsui Shipbuilding and Engineering 503,261 4/1939 Great Britain l23/DIG. 6

Company, Ltd.; Japan Ships Machinery Development Association, Primary Examiner-Wendell E. Burns both of Tokyo, Japan Attorney, Agent, or FirmI-lowson and Howson; 22 Filed: Apr. 12, 1972 Henry Skmma [21] Appl. No.: 243,128

[57] ABSTRACT Foreign Application Priority Data Method of taking the piston from the engine in the in- May 27, 1971 Japan 46-36822 temal combustion engine, more particularly in the trunk piston engine, characterized by that the con- [52] US. Cl 123/195 1R, 92/128, 92/171, necting rod is disconnected from the piston and 123/1, l23/DIG. 6 turned to a suitable position in the crankcase, the pis- [51] Int. Cl. 1F 02f 7/00 ton is drawn out of the cylinder to the crankshaft and [578] Field of Search l23/DIG. 6, 195 R; 92/ 128 supported on the crankshaft, and the crankshaft is rotated together with the piston to the position where [56] References Cited the piston is taken out of the engine.

UNITED STATES PATENTS 10/1897 Bole 92/128 6 Claims, 10 Drawing Figures PAIENTEBmzz m4 1 sum 2 or z FIG. 6

FIG. 8

METHOD AND APPARATUS FOR TAKING OUT PISTON IN TRUNK PISTON ENGINE This invention relates to a method and apparatus for taking out piston in trunk piston engine. In the usual engines, for the purpose of inspection of the piston, the piston is taken from the engine by removing a cylinder head cover and then upwardly drawing a piston. In order to perform the removing work of the cylinder head cover, such associated works as separation of the cylinder head piping, separation of valve actuating mechanisms and releasing of cylinder head cover fastening bolts are necessary, which requires much labor.

Therefore, an object of the present invention is to overcome the above conventional drawbacks by the provision of a method, which enables taking the piston to the outside of the engine with a minimum of necessary works.

To this end, in accordance with the present invention the connecting rod is disconnected from the piston, the connecting rod is turned to a suitable position within the crankcase, the piston is taken out of the cylinder into the crankcase and supported on the crankshaft, thereafter the crankshaft is rotated, so that the piston is moved to the opening of the crankcase, where the piston can be readily taken from the engine.

In the drawings:

FIGS. I to 4 illustrate a method of taking the piston according to the present invention applied to a V-type engine;

FIG. 5 is a section taken on line A-A in FIG. 3;

FIG. 6 to 9 show also the method according to the present invention applied to a straight type engine; and

FIG. is a section taken on line B-B in FIG. 8.

The present invention will now be described in conjunction with FIG. 1, connecting rod 3 consists of two parts 3a and 3b removably connected at 5 by bolts 6. Crankshaft 7 carries a balance weight 8 secured to it, the balance weight is formed with a recess 9, into which the piston 2 can be inserted.

To take the piston from the engine, the crankshaft is turned to bring the piston to be taken to the bottom dead point thereof, as shown in FIG. I. Thereafter, by releasing the bolts 6 the upper and lower halves 3a and 3b of the connecting rod are separated from each other. The lower connecting rod half 3b is turned to a a suitable position within the crankcase by turning the crankshaft or by rotating it about the crankpin without separating it from the crankshaft as shown in FIG. 2. Then, the crankshaft is again rotated to the bottom dead point to bring the weight 8 into a position directly beneath the piston leaving the connecting rod in the position, as shown in FIG. 3. Thereafter, the piston 2 is drawn downwardly from the cylinder and inserted into the recess 9 of the balance weight 8 (FIG. 3), the crankshaft is rotated with the piston held in the recess to bring the piston to a position in front of the oil door. Thus the piston can be taken out in the direction of arrow. Instead of or in addition to the balance weight 8, a suitable member may be attached to the crankshaft for the same operation as mentioned above.

The assemblage of the piston into the engine is performed in the reverse order of above mentioned steps.

FIGS. 6 to 10 show another embodiment of the present invention applied to a straight type engine. In these drawings, the same parts as those in the preceding embodiment are designated by same reference numerals as those used in the preceding drawings. The taking and assembling of the piston can be done in the same way as in the preceding embodiment.

As described in the foregoing, according to the present invention the piston which is assembled in the engine can be taken out with a minimum of work without removing the cylinder head cover, so that the time and labor required for the inspection and maintenance may be greatly decreased.

What is claimed is: v

1. In a trunk piston engine having a crankshaft rotatable about an axis of revolution, a crank on said shaft offset to one side of said axis of revolution, and a balance weight offset to the opposite side of said axis of revolution, a cylinder in said engine having its axis disposed radial to said axis of revolution, a piston mounted for axial displacement in said cylinder, and a connecting rod having means at one end rotatably mounting said rod on said crank and means at the other end rotatably mounting said rod on said piston, whereby rotation of said crankshaft on its axis of rotation reciprocates said piston in said cylinder, the method of removing the piston comprising the steps of disconnecting the connecting rod from the piston at said other end of the rod, rotating said connecting rod away from said cylinder and providing a support for the disconnected end of said rod, positioning said balance weight in confronting relation to said cylinder, drawing the piston toward said axis of rotation a distance sufficient to disengage said piston from said cylinder and to engage said piston with said balance weight, rotating said balance weight with the piston engaged thereon to a convenient position for removal of said piston from said engine, and thereupon removing said piston from said engine.

2. A method according to claim 1 wherein the balance weight of said engine consists of a bifurcated member having a radial recess therein for receiving said piston, including the step of telescopically engaging said piston in said recess during removal of said piston from said cylinder.

3. A method according to claim I wherein the displacement of said connecting rod and the displacement of said balance weight with the piston engaged thereon are both effected by rotating the crankshaft about its axis of rotation.

4. A method according to claim 1 including the step of providing a releasable connection between said connecting rod and said mounting means for said piston at a point between the inner end of the cylinder and the axis or rotation of thecrankshaft when said crank is positioned furtherest away from said cylinder whereby upon disconnection of said connecting rod from said piston, the free end of said connecting rod clears the inner end of said cylinder.

5. A trunk piston engine having a crankshaft rotatable about an axis of revolution, a crank on said shaft offset to one side of said axis of revolution, a bifurcated balance weight offset to the opposite side of said axis of revolution in transverse alignment with said crank, a connecting rod having means at one end rotatably mounting said rod on said crank and operable to rotate in a plane perpendicular to said axis of revolution between the bifurcations of said balance weight, a cylindeer in said engine having its axis disposed radial to said axis of revolution within said plane, a piston mounted for axial displacement in said cylinder, means rotatably mounting the other end of said rod on said piston, whereby rotation of said crankshaft on its axis of rotation reciprocates said piston in said cylinder, said rod having a releasable connection between said connecting rod and said mounting means for said piston at a point between the inner end of said cylinder and the axis of rotation of the crankshaft when the crank is positioned furtherest away from said cylinder so that upon disconnection of said connecting rod from said piston by said releasable connection, the free end of said connecting rod clears the inner end of said cylinder, and means on said balance weight to engage and support piston clears the inner end of said cylinder. 

1. In a trunk piston engine having a crankshaft rotatable about an axis of revolution, a crank on said shaft offset to one side of said axis of revolution, and a balance weight offset to the opposite side of said axis of revolution, a cylinder in said engine having its axis disposed radial to said axis of revolution, a piston mounted for axial displacement in said cylinder, and a connecting rod having means at one end rotatably mounting said rod on said crank and means at the other end rotatably mounting said rod on said piston, whereby rotation of said crankshaft on its axis of rotation reciprocates said piston in said cylinder, the method of removing the piston comprising the steps of disconnecting the connecting rod from the piston at said other end of the rod, rotating said connecting rod away from said cylinder and providing a support for the disconnected end of said rod, positioning said balance weight in confronting relation to said cylinder, drawing the piston toward said axis of rotation a distance sufficient to disengage said piston from said cylinder and to engage said piston with said balance weight, rotating said balance weight with the piston engaged thereon to a convenient position for removal of said piston from said engine, and thereupon removing said piston from said engine.
 2. A method according to claim 1 wherein the balance weight of said engine consists of a bifurcated member having a radial recess therein for receiving said piston, including the step of telescopically engaging said piston in said recess during removal of said piston from said cylinder.
 3. A method according to claim 1 wherein the displacement of said connecting rod and the displacement of said balance weight with the piston engaged thereon are both effected by rotating the crankshaft about its axis of rotation.
 4. A method according to claim 1 including the step of providing a releasable connection between said connecting rod and said mounting means for said piston at a point between the inner end of the cylinder and the axis or rotation of the crankshaft when said crank is positioned furtherest away from said cylinder whereby upon disconnection of said connecting rod from said piston, the free end of said connecting rod clears the inner end of said cylinder.
 5. A trunk piston engine having a crankshaft rotatable about an axis of revolution, a crank on said shaft offset to one side of said axis of revolution, a bifurcated balance weight offset to the opposite side of said axis of revolution in transverse alignment with said crank, a connecting rod having means at one end rotatably mounting said rod on said crank and operable to rotate in a plane perpendicular to said axis of revolution between the bifurcations of said balance weight, a cylinder in said engine having its axis disposed radial to said axis of revolution within said plane, a piston mounted for axial displacement in said cylinder, means rotatably mounting the other end of said rod on said piston, whereby rotation of said crankshaft on its axis of rotation reciprocates sAid piston in said cylinder, said rod having a releasable connection between said connecting rod and said mounting means for said piston at a point between the inner end of said cylinder and the axis of rotation of the crankshaft when the crank is positioned furtherest away from said cylinder so that upon disconnection of said connecting rod from said piston by said releasable connection, the free end of said connecting rod clears the inner end of said cylinder, and means on said balance weight to engage and support said piston after disconnection of said connecting rod and displacement of said piston radially inward out of said cylinder.
 6. An engine according to claim 5 wherein said bifurcated balance weight is provided with a radial recess adapted to telescopically receive said piston upon disengagement of said releasable connection, the depth of said recess permitting radial displacement of said piston inwardly a distance such that the outer end of said piston clears the inner end of said cylinder. 